1. Field of the Invention
The invention relates to a magnet structure, particularly for Nuclear Magnetic Resonance imaging machines and of the type comprising a bearing structure for generating magnetic fields inside a volume, a cavity or similar space, defined by the structure.
The invention particularly relates, but is not limited, to magnet structures for Nuclear Magnetic Resonance imaging machines of the type known as dedicated machines, i.e., designed for Nuclear Magnetic Resonance imaging of individual parts of the body, and in which the volume or cavity are such that they generally do not house therein the whole patient, or a considerable part thereof, but only the part limited to one of a few limbs or body regions.
One aspect of the invention relates to magnet structures for permanent magnets.
2. Description of Related Art
Prior art magnet structures have a bearing structure generally made of a ferromagnetic or high-permeability material, with layers of magnetized material, eventually associated with further layers of a more or less permeable material, being fixed thereto in a predetermined position. Although, in dedicated machines, the magnet structure is dimensionally reduced, it is still considerably large.
The fabrication of magnets also requires a high accuracy in dimensioning and mutually positioning the parts forming the structure. This requirement is urged by the fact that, inside the relevant volume wherein the body or the part thereof under examination has to be received, the magnetic field must have high homogeneity characteristics.
The manufacture of the parts forming the magnet structure with the required high accuracy in shape and dimensions and the considerable size of said parts are contrasting needs, which may be integrated only with a considerable cost increase.